This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Patent Application No. 2001-299694 filed on Sep. 28, 2001, the entire content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a hybrid car using both an electric motor driven by electric power stored in a battery and an internal combustion engine driven by combustion energy of internally burned fuel as sources for driving travel wheels.
2. Description of the Related Art
There can be used a hybrid car which is improved in fuel economy by about twice and in reduction of carbon dioxide emission by about a half compared with an ordinary automobile and in which emissions of nitrogen oxide, carbon hydride, etc. can be reduced to be not larger than a quarter of the regulated value of Exhaust Emission Standard for 2000.
This hybrid car uses both an electric motor driven by electric power stored in a battery and an internal combustion engine driven by combustion energy of internally burned fuel as sources for driving travel wheels. The electric motor and the internal combustion engine are operated in accordance with the travel state or the like so that the characteristics of the electric motor and the internal combustion engine can be used effectively. Thus, reduction both in fuel consumption and in exhaust emission is achieved.
On the other hand, provision of restricted areas in urban regions, semi-national parks, etc. for environmental protection is under consideration so that riding in automobiles such as gasoline-powered automobiles that emit exhaust gases when travel is completely restricted in the restricted area. Only automobiles such as electric automobiles that do not emit exhaust gases are permitted to pass through such restricted areas.
When a restricted area forbidden for automobiles that emit exhaust gases is between a current position of the hybrid car and a destination, the hybrid car needs to bypass the restricted area because the hybrid car more or less emits exhaust gases when traveling. Hence, there is a problem that the hybrid car takes a long time to arrive at the destination.
It may be conceived now that only the electric motor is driven to make the hybrid car pass through the restricted area so that exhaust gases are not emitted from the hybrid car. Electric energy stored in the battery of the hybrid car, however, always varies. Hence, electric energy sufficient to make the hybrid car pass through the restricted area is not always stored in the battery. Hence, there is a problem that the hybrid car may be unable to pass through the restricted area.
An object of the present invention is to provide a hybrid car which can reach a destination via a restricted area forbidden for automobiles that emit exhaust gases even in the case where the restricted area is between the current position of the hybrid car and the destination.
According to a first aspect of the invention, there is provided a hybrid car using both an electric motor driven by electric power stored in a battery and an internal combustion engine driven by combustion energy of internally burned fuel as sources for driving travel wheels, the hybrid car including: a restricted area detecting unit for detecting whether a restricted area forbidden for automobiles driven by internal combustion engines is forward in a direction of movement of the hybrid car or not, and detecting arrival of the hybrid car at the restricted area; and a travel mode switching unit for selecting one mode from a motor travel mode using only the electric motor to run the hybrid car and an ordinary travel mode using the electric motor and/or the internal combustion engine suitably to run the hybrid car, on the basis of a detection result detected by the restricted area detecting unit.
There is the case where an ETC (Electronic Toll Charge system) is provided in a toll road so that entrance into the toll road is detected by a receiver which receives electric wave from a transmission antenna provided in front of an entrance ramp of the toll road.
As the restricted area detecting unit, there can be used a unit which has an ETC type receiver for receiving electric wave from a transmission antenna provided in each place in front of an entrance of the restricted area in the same manner as in the ETC to thereby detect the presence and distance of the restricted area forward in a direction of movement of the hybrid car and entrance into the retrained zone.
Alternatively, as the restricted area detecting unit, there can be used a unit which has a receiver for receiving information from a VICS (Vehicle Information Communications System) supplying road and traffic information concerning a road (on which automobiles are traveling) and its vicinity as digital information, and a GPS (Global Positioning System) receiver for locating the current position by using an artificial satellite and in which the presence and distance of the restricted area forward in a direction of movement of the hybrid car and entrance into the restricted area can be detected by these receivers. Alternatively, as the restricted area detecting unit, there can be used a unit in which the presence and distance of the restricted area forward in a direction of movement of the hybrid car and entrance into the restricted area can be detected by a navigation system having map information stored therein and having a GPS receiver.
In the first aspect of the invention, when the hybrid car is traveling in the ordinary travel mode, electric power can be accumulated as follows. That is, the battery is controlled so that charging electric energy is higher than discharging electric energy, or an exclusive battery for supplying electric power to the electric motor in the motor travel mode is provided separately so that the exclusive battery can be charged in the ordinary travel mode. In this configuration, when the restricted area detecting unit detects a restricted area forward in the direction of movement of the hybrid car, electric power is accumulated before the hybrid car arrives at the restricted area. Therefore, when the hybrid car arrives at the restricted area, the travel mode switching unit switches the travel mode from the ordinary travel mode to the motor travel mode, and, at the same time, the electric motor can be driven by the accumulated electric power. Hence, only the electric motor can be used for traveling the hybrid car to make the hybrid car pass through the restricted area.
Moreover, arrival of the hybrid car at the restricted area can be automatically detected by the restricted area detecting unit. Hence, when the hybrid car arrives at the restricted area, the travel mode can be automatically switched from the ordinary travel mode using both the electric motor and the internal combustion engine as drive sources to the motor travel mode using only the electric motor as a drive source. As a result, the internal combustion engine is prevented from being operated in the restricted area, so that environmental protection in the restricted area can be achieved.
According to a second aspect of the invention, there is provided a hybrid car using both an electric motor driven by electric power stored in a battery and an internal combustion engine driven by combustion energy of internally burned fuel as sources for driving travel wheels, the battery being rechargeable when the internal combustion engine is driven, the hybrid car including: a restricted area detecting unit for detecting whether a restricted area forbidden for automobiles driven by internal combustion engines is forward in a direction of movement of the hybrid car or not, and detecting arrival of the hybrid car at the restricted area; a required electric energy calculating unit for calculating electric energy required for making the hybrid car pass through the restricted area so that only the electric motor can be operated to make the hybrid car pass through the restricted area; a battery-charge operating time calculating unit for calculating battery-charge operating time required for storing the required electric energy in the battery; a start point calculating unit for calculating a start point for starting a battery-charge operation on the basis of the battery-charge operating time calculated by the battery-charge operating time calculating unit; and a travel mode switching unit for selecting one mode from a battery-charge travel mode for charging the battery during traveling of the hybrid car, a motor travel mode using only the electric motor to run the hybrid car and an ordinary travel mode using the electric motor and the internal combustion engine suitably to run the hybrid car, on the basis of a detection result detected by the restricted area detecting unit and the start point calculated by the start point calculating unit.
In the second aspect of the invention, the restricted area detecting unit is formed in the same manner as in the first aspect of the invention. That is, as the restricted area detecting unit, there can be used as a unit which has an ETC type receiver for receiving electric wave from a transmission antenna provided in each place in front of an entrance of the restricted area to thereby detect the presence and distance of the restricted area forward in the direction of movement of the hybrid car and entrance into the restricted area. Alternatively, as the restricted area detecting unit, there can be used a unit which has a receiver for receiving information from a VICS supplying road and traffic information concerning a road (on which automobiles are traveling) and its vicinity as digital information, and a GPS receiver for locating the current position by using an artificial satellite and in which the presence and distance of the restricted area forward in a direction of movement of the hybrid car and entrance into the restricted area can be detected by these receivers. Alternatively, as the restricted area detecting unit, there can be used a unit in which the presence and distance of the restricted area forward in a direction of movement of the hybrid car and entrance into the restricted area can be detected by a navigation system having map information stored therein and having a GPS receiver.
As in the second aspect of the invention, when the restricted area detecting unit automatically detects a restricted area forward in the direction of movement of the hybrid car, the required electric energy calculating unit calculates electric energy required for operating only the electric motor to make the hybrid car pass through the restricted area, and the battery-charge operating time calculating unit calculates battery-charge operating time to be secured. Then, the start point calculating unit calculates a start point on the basis of the battery-charge operating time so that a battery-charge operation can be started at the start point. When the hybrid car reaches the start point, the travel mode switching unit automatically selects the batter-charge travel mode. Hence, when the hybrid car arrives at the restricted area, electric power sufficient to make the hybrid car pass through the restricted area is stored in the battery so that the hybrid car can pass through the restricted area.
Moreover, arrival of the hybrid car at the restricted area can be automatically detected by the restricted area detecting unit in the same manner as in the first aspect of the invention. Hence, when the hybrid car arrives at the restricted area, the travel mode is automatically switched from the ordinary travel mode using both the electric motor and the internal combustion engine as drive sources to the motor travel mode using only the electric motor as a drive source. As a result, the internal combustion engine is prevented from being operated in the restricted area, so that environmental protection in the restricted area can be achieved.
In the hybrid car, preferably, a navigation system is provided for receiving current position information to measure a current position of a mobile body and indicating the current position on a screen displayed on a display device on the basis of map information stored in the navigation system, and the restricted area detecting unit permits the navigation system to search the map information to thereby detect whether the restricted area is forward in the direction of movement of the hybrid car or not.
In this configuration, detection of the restricted area can be ensured by the navigation system. Moreover, the arrival time required for making the hybrid car arrive at the restricted area and the mileage, height difference and travel time required for making the hybrid car pass through the restricted area can be calculated accurately by the navigation system. Hence, electric energy required for making the hybrid car pass through the restricted area and battery-charge operating time required for charging the battery with the required electric energy can be calculated accurately. When the battery is charged in practice, surplus electric energy generated excessively to ensure the passage of the hybrid car through the restricted area can be reduced. As a result, wasteful energy consumed therefor can be reduced.
Further preferably, in the hybrid car, the navigation system has a route retrieval function for retrieving a route to a destination, and the restricted area detecting unit detects the restricted area on the basis of whether the route retrieved by the navigation system passes through the restricted area or not.
In this configuration, the shortest route to the destination can be found by the navigation system. Moreover, when a restricted area is on the shortest route, the restricted area is detected by the restricted area detecting unit so that a battery-charge operation required for making the hybrid car pass through the restricted area can be carried out securely. As a result, the hybrid car can arrive at the destination while traveling on the shortest route, so that the hybrid car can arrive at the destination in the shortest time.
According to a third aspect of the invention, there is provided a hybrid car using both an electric motor driven by electric power stored in a battery and an internal combustion engine driven by combustion energy of internally burned fuel as sources for driving travel wheels, the battery being rechargeable when the internal combustion engine is driven, the hybrid car including: a restricted area detecting unit for detecting whether a restricted area forbidden for automobiles driven by internal combustion engines is forward in a direction of movement of the hybrid car or not, and detecting arrival of the hybrid car at the restricted area; a required electric energy calculating unit for calculating electric energy required for making the hybrid car pass through the restricted area so that only the electric motor can be operated to make the hybrid car pass through the restricted area; a residual electric energy predicting unit for predicting residual electric energy which will remain in the battery at a point of time when the hybrid arrives at the restricted area; and a bypass instruction unit for comparing the residual electric energy and the required electric energy with each other and outputting a bypass instruction signal when the required electric energy is higher than the residual electric energy.
In the third aspect of the invention, a car having an ETC type receiver as described above, a car having a VICS receiver and a GPS receiver, or a car having a navigation system can be used in the same manner as in the first and second aspects of the invention.
As in the third aspect of the invention, when a restricted area forward in the direction of movement of the hybrid car is automatically detected by the restricted area detecting unit, electric energy required for operating only the electric motor to make the hybrid car pass through the restricted area is calculated by the required electric energy calculating unit and residual electric energy which will remain in the battery at a point of time when the hybrid car arrives at the restricted area is predicted by the residual electric energy predicting unit so that the required electric energy and the residual electric energy are compared with each other by the bypass instruction unit.
When the residual electric energy is higher than the required electric energy, only the electric motor can be driven to make the hybrid car pass through the restricted area.
When the residual electric energy is lower than the required electric energy, shortage of the residual electric, energy is reported by the bypass instruction unit. Hence, a bypass can be found from a map or the like so that the residual electric energy covers the whole distance of the bypass. As a result, the hybrid car can pass through the restricted area.
In the hybrid car, preferably, a navigation system is provided for receiving current position information to measure a current position of a mobile body and indicating the current position on a screen displayed on a display device on the basis of map information stored in the navigation system, and the restricted area detecting unit permits the navigation system to search the map information to thereby detect whether the restricted area is forward in the direction of movement of the hybrid car or not.
In this configuration, detection of the restricted area can be ensured by the navigation system. Moreover, the arrival time required for making the hybrid car arrive at the restricted area and the mileage, height difference and travel time required for making the hybrid car pass through the restricted area can be calculated accurately by the navigation system. Hence, electric energy required for making the hybrid car pass through the restricted area can be calculated accurately, and residual electric energy which will remain in the battery at a point of time when the hybrid car arrives at the restricted area can be predicted accurately, so that judgment for bypassing the restricted area can be made accurately. Moreover, when a by pass is retrieved by the navigation system so that the residual electric energy can cover the whole distance of the bypass, the hybrid car can pass through the restricted area securely.
In the hybrid car, further preferably, the navigation system has a route retrieval function for retrieving a route to a destination, and the restricted area detecting unit detects the restricted area on the basis of whether the route retrieved by the navigation system passes through the restricted area or not.
In this configuration, the shortest route to the destination can be found by the navigation system. Moreover, when the bypass instruction unit issues a bypass instruction signal, a route to the destination is retrieved again by the navigation system on the basis of the residual electric energy so that the shortest bypass can be found. Thus, the hybrid car is made to run on the shortest bypass. As a result, the hybrid car can reach the destination by traveling on the selectable shortest route, so that the hybrid car can reach the destination in the shortest time.